The　cable　dynamic　stiffness　describes　the　load-deformation　behavior　of　cables　subjected　to　dynamic　loading.　It　represents　the　intrinsic　dynamic　properties　of　cables.　For　the　purpose　of　identification　for　cable　modal　parameter,　the　simplified　cable　dynamic　stiffness　is　proposed　based　a　closed-form　expression　of　dynamic　stiffness　taking　cable　sag　into　account.　A　series　of　cable　modal　tests　were　conducted　in　the　laboratory　with　different　cable　tension　levels　and　corresponding　frequency　response　functions　were　obtained.　Based　on　the　proposed　simplified　cable　dynamic　stiffness　and　measured　frequency　response　functions,　the　cable　frequencies　and　damping　ratios　have　been　successfully　identified　by　using　a　least　square　curve　fitting　technique.　Subsequently,　a　new　method　to　estimate　the　modal　parameters　of　cables　is　established.